WASHINGTON — The U.S. Air Force’s current-generation missile warning satellites each carry two main infrared sensors, but a new study by prime contractor Lockheed Martin concludes that a new version carrying a single sensor could offer nearly the same performance.

The study was carried out as part of an Air Force effort to trim hundreds of millions of dollars from the cost of its next two Space Based Infrared System satellites, known as GEO-7 and GEO-8.

On average, the current SBIRS satellites have taken about seven years to build at a cost of about $1.1 billion each, a figure that has drawn criticism from budget conscious lawmakers. Air Force officials want to cut the price tag of the next satellites by 30 percent or more and in March put Lockheed Martin under contract to study how to do so.

According to an Air Force report dubbed “Procurement of Space-Based Infrared Systems” and delivered to congressional defense committees in September, the Lockheed Martin exercise examined several changes including simplifying the sensor and other SBIRS mechanical systems, technology upgrades, and addressing obsolescence issues.

The Air Force report was a response to a request from House members who had asked for greater detail on how the service was using the estimated $1 billion it saved by buying the fifth and sixth SBIRS satellites together rather than serially.

The Lockheed Martin study is wrapping up now, said Neil Goodzeit, military space chief architect at Sunnyvale, California-based Lockheed Martin Space Systems, who led the effort. One of the highlights, Goodzeit said in a Dec. 3 interview, has been its examination of new SBIRS payload configurations.

Each geosynchronous SBIRS satellite has two main infrared sensors: a scanning sensor that sweeps over large swaths of territory watching for missile launches, and a staring sensor that can be trained constantly on a smaller area of interest to provide near-immediate notification of launches.

Goodzeit said the study examined both dual and single-sensor configurations, each with different performance levels and costs. He declined to specify which configurations worked best, but said that some offered an improvement over the existing SBIRS satellites.

Lockheed Martin examined other potential cost-cutting options including switching to an updated version of Lockheed Martin’s signature A2100 satellite platform — the company is revamping that product line to make it simpler and less expensive —  simplifying subsystems, and streamlining the payload integrating and testing process, executives said.

In addition, the study took a look at the idea of replacing the image-recording focal planes on the satellites’ main sensors with modern digital focal planes. In May, the Air Force said that making such a change on the fifth and sixth SBIRS satellites would add at least $424 million to their cost and delay their delivery by nearly two years.

But lawmakers have pushed for the upgrade. The Lockheed Martin study said such a swap could lead to a higher-performance and a simpler payload, which ultimately  would reduce satellite production time and costs.

David Sheridan, a Lockheed Martin Space Systems vice president and the SBIRS program manager, said the company is very confident it could achieve 30 percent savings on recurring costs.

As part of its Space Modernization Initiative, the Air Force spent $5 million in 2014 and plans to spend $11.5 million in 2015 on what it calls Evolved SBIRS, the next iteration of the program. While lawmakers have balked at providing some of those funds, particularly those earmarked for examining alternative systems, they have generally supported the program of record.

A total of six SBIRS satellites are under contract to Lockheed Martin; two of those have been launched to date.

The Air Force is still working on an analysis of future missile warning alternatives. The analysis was expected to wrap up in December, according to a recent Government Accountability Office report.

If the Air Force chooses to continue buying SBIRS satellites in one form or another, the service would begin studies to examine Lockheed Martin’s proposals in more detail, the Air Force’s report to Congress said.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.